The aims of this study are to conduct a carefully controlled evaluation of the effectiveness of behavioral Family Systems Therapy with female adolescents diagnosed as having anorexia nervosa, using psychometrically sound dependent measures and adequate follow-up procedures. Forty 12 to 17 year old females meeting the DSM III criteria or anorexia nervosa and their parents will be randomly assigned to either Behavioral Family Systems Therapy (BFST) or Ego Oriented Individual Therapy (EOIT)- Treatment will be conducted primarily on an outpatient basis by a team of a psychologist, a pediatrician, and a dietitian. Treatment will consist of 12 months of hour sessions, 8 months weekly during weight gain and 4 months bimonthly during weight maintenance. with the parents and adolescent present for all sessions, BFST blends a behavioral program for weight restoration, cognitive restructuring for correcting faulty beliefs and distorted perceptions, and strategic structural family therapy techniques for changing family interactions. EOIT consists of individual psychotherapy for the adolescent focused on autonomy, strength, and psychosocial development, fostering insight into the precipitants of the anorexia. Bimonthly collateral sessions are held with the parents. A multidimensional battery of measures will be administered at pre-assessment, six months later, at termination, and at a 12 month follow-up. These include weight, medical measures, eating/body image measures, psychopathological measures, family measures, and Morgan outcome ratings, as well as assessments of parental and sibling functioning. Following a- priori defined linear compositing of major variables, multivariate a-priori contrasts will be used to analyze the effects of treatment and changes over time, with careful controls for experiment-wise error rates.